#pragma once

#include <iostream>
#include <string>
#include <unistd.h>
#include <cerrno>
#include <cstring>
#include <cstdlib>
#include <functional>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

namespace Server
{
    using namespace std;
    static const string defaultIp = "0.0.0.0";
    static const int gnum = 1024;

    typedef function<void (int, string, uint16_t, string)> func_t;

    enum
    {
        USAGE_ERR = 1,
        SOCKET_ERR, 
        BIND_ERR,
        OPEN_ERR
    };

    class udpServer
    {
    public:
        udpServer(const func_t &cb, const uint16_t &port, const string &ip = defaultIp)
         :_callback(cb), _port(port), _ip(ip), _sockfd(-1)
        { }

        void initServer()
        {
            // 1.创建socket
            _sockfd = socket(AF_INET, SOCK_DGRAM, 0);
            if (_sockfd == -1)
            {
                cerr << "socket error: " << errno << " : " << strerror(errno) << endl;
                exit(SOCKET_ERR);
            }
            cout << "socket success: " << _sockfd << endl;

            // 2.绑定port,ip
            // 未来服务器需要明确的port,不能随意改变
            struct sockaddr_in local;// 定义一个变量 -> 栈 -> 用户
            bzero(&local, sizeof(local));
            local.sin_family = AF_INET;
            local.sin_port = htons(_port);// 如果你要给别人发消息,port和ip要发送给对方
            // 大端还是小端? -> htons转化
            local.sin_addr.s_addr = inet_addr(_ip.c_str());// 1.string->uint32_t 2.htonl()
            // local.sin_addr.s_addr = htonl(INADDR_ANY);// 任意地址bind,服务器的真实写法,htonl可加可不加
            int n = bind(_sockfd, (struct sockaddr*)&local, sizeof(local));
            if (n == -1)
            {
                cerr << "bind error: " << errno << " : " << strerror(errno) << endl;
                exit(BIND_ERR);
            }   
        }

        void start()
        {
            // 服务器的本质就是一个死循环
            char buffer[gnum];
            for(;;)
            {
                // 读取数据
                struct sockaddr_in peer;
                socklen_t len = sizeof(peer);// 必填
                ssize_t s = recvfrom(_sockfd, buffer, sizeof(buffer) - 1, 0, (struct sockaddr*)&peer, &len);
                // 数据是什么 谁发的
                if(s > 0)
                {
                    buffer[s] = 0;
                    string clientip = inet_ntoa(peer.sin_addr);// 1.网络序列 2.int -> 点分十进制Ip
                    uint16_t clientport = ntohs(peer.sin_port);
                    string message = buffer;

                    cout << clientip << "[ " << clientport << " ]# " << message << endl;
                    _callback(_sockfd, clientip, clientport, message);
                }
            }
        }

        ~udpServer()
        {
        }

    private:
        uint16_t _port;
        std::string _ip;
        int _sockfd;
        func_t _callback;// 回调
    };
}